Poyang Lake is the largest freshwater lake in China with a catchment area of 162000km2.The only outlet to the Changjiang River is at Hukou.The flood regimes in the lake are mainly controlled by the Changjiang River and the 5 tributaries to the lake.The reclamation in the lake area may be traced back to the Song Dynasty.The benefits of reclamation to mankind were inevitably hampered due to the frequent, natural flooding.It was estimated that an area of 15.8 km² had been reclaimed before 1949, among which the standards of many dykes were too low to resist heavy flooding.After 1949, the economic growth as well the urgency for eliminating popular snail fever in the lake beach triggered the large-scale reclamation movement around the lake.Up to 1995, statistics show that a total area of 1466.9km2 has been reclaimed, which brought a series of unfavorable influences on the flood regimes of the lake, such as: (1) the shrinkage of lake area and capacities, (2) the deterioration of flood regulating and functioning, and (3) the ascending of peak floods and corresponding frequencies.The impacts of reclamation on the flood regime of Poyang Lake are analyzed.Five represent -ative flood years, i.e., 1954, 1962, 1976, 1983 and 1995 are selected? as backgrounds for estimation.Comparisons are made between the calculated and observed flood characters of certain typical flood years under present reclamation conditions.Furthermore, the supposing flood peak changes conditioning future reclamation/de-reclamation based on 1954-type flood processes under present vsituation are given.The more de-reclamation, the more will flood regime be alleviated.